Natural calcium carbonate Marble

Although sodium carbonate is needed in the manufacture of glass, very little is found in nature. It is made using two very abundant chemicals, calcium carbonate (marble) and sodium chloride (salt). The process involves many steps, but the overall reaction is... 

SYNS AGRICULTURAL LIMESTONE AGSTONE ARAGONITE ATOMIT BELL MINE PULVERIZED limestone CALCITE CARBONIC ACID, CALCIUM SALT (1 1) CHALK DOLOMITE FRANKLIN D LIMESTONE (FCC) LITHOGRAPHIC STONE MARBLE NATURAL CALCIUM CARBONATE PORTLAND STONE SOHNHOFEN STONE VATERITE... 

Calcite. A common crystalline form of natural calcium carbonate, caco3, that is the basic constituent of limestone, marble, and chalk. Also called calcspar. 

Synonyms/Trade Names Calcium carbonate. Natural calcium carbonate [Note Marble is a metamorphicform of calcium carbonate.] ... 

Synonyms Agricultural limestone Calcite Calcium carbonate natural Chalk Cl 77220 Dolomite Franklin Limestone Lithographic stone Marble Natural calcium carbonate Paris white Pigment white 18 Portland stone Vaterlte Whiting Classification Inorganic salt... 

All commercial grades of natural calcium carbonate are based upon deposits of calcite, which vary in purity, colour and crystallite size. These factors depend upon genesis and subsequent temperature-pressure history. Chalk is usually off-white in colour and is composed of small crystals which are easily disintegrated. Marble, by metamorphosis, has large crystals and very white deposits can be found. Limestone is one of a number of intermediate forms and varies from white to grey or buff in colour, due mainly to iron impurities. 

Calcium carbonates can occur naturally in the form of chalk, limestone, marble, etc., from which the filler is obtained by fine milling or synthesized by precipitation. Due to its low price and to the improvement of polymer properties and aging resistance, natural calcium carbonate is the most important filler used in plastics. Small amounts of finely dispersed CaC03, silica, or various silicates reduce sticking and improve the paperlike feel of PE films. 

Synonyms Agricultural limestone Allied whiting Calcite Calcium carbonate (INCI) Calcium carbonate (1 1) Calcium carbonate, precipitated Calcium monocarbonate Carbonic acid calcium salt Carbonic acid calcium salt (1 1) Chalk Cl 77220 Dolomite Drop chalk English white Franklin Limestone Lithographic stone Marble Monocalcium carbonate Natural calcium carbonate Paris white Pigment white 18 Portland stone Precipitated calcium carbonate Precipitated chalk Prepared chalk Vaterite Vienna white White powder Whiting Classification Inorganic salt... 

Calcium. Calcium is the fifth most abundant element in the earth s cmst. There is no foreseeable lack of this resource as it is virtually unlimited. Primary sources of calcium are lime materials and gypsum, generally classified as soil amendments (see Calcium compounds). Among the more important calcium amendments are blast furnace slag, calcitic limestone, gypsum, hydrated lime, and precipitated lime. Fertilizers that carry calcium are calcium cyanamide, calcium nitrate, phosphate rock, and superphosphates. In addition, there are several organic carriers of calcium. Calcium is widely distributed in nature as calcium carbonate, chalk, marble, gypsum, fluorspar, phosphate rock, and other rocks and minerals. 

Whiting at one time coimoted only a very fine form of chalk of micrometer sizes but the term is now used more broadly to include all finely divided, meticulously milled carbonates derived from high calcium or dolomitic limestone, marble, shell, or chemically precipitated calcium carbonate. Unlike all of the above natural forms of limestone, it is strictly a manufactured product. 

Calcium carbonate, available both from natural sources and as precipitated forms (see Calcium compounds), is most useful in coating because of purity and high brightness, ie, 90—95%. Ground carbonates from marble deposits have high purity levels as do the carbonates from some chalk deposits. 

The most common compound of calcium is calcium carbonate, CaC03, which occurs naturally in a variety of forms such as chalk and limestone. Marble is a dense form of calcium carbonate that can be given a high polish it is often colored... 

Carbon dioxide is present in air and is a constituent of natural gas escaping from mineral springs and fissures in the earth s surface. It is also the ultimate product of combustion of carbon and its compounds. Laboratory scale preparation usually entails reaction between dilute hydrochloric acid and marble (calcium carbonate) ... 

Most elements, however, are naturally combined with one or more other elements, forming compounds. Water and calcium carbonate (also known as calcite, limestone, or marble) are examples of common compounds formed by the combination of two or more elements in water, one atom of oxygen is combined with two of hydrogen and in calcium carbonate, one atom of carbon is combined with three of oxygen and one of calcium. 

Finely-divided calcium carbonate obtained from natural sources (chalk, limestone or marble) or as a by-product of another chemical process -precipitated whiting. Strictly speaking, the term whiting should be applied only to material prepared by grinding natural chalk . 

Calcium carbonate (CaCO ) can be in the form of an odorless crystal or powder and is one of calcium s most stable compounds, better known in its natural state as limestone, marble, chalk, calcite, oyster shells, and the minerals marl and travertine. Calcium carbonate is the source of lime and is used as a filler for many products, including paints, plastics, and foods (bread), and as an antacid. 

Calcium carbonate occurs in nature as hmestone in various forms, such as marble, chalk, and coral. It is probably the most widely-used raw material in the chemical industry. It has numerous apphcations, primarily to produce cement, mortars, plasters, refractories, and glass as budding materials. It also is used to produce quicklime, hydrated lime and a number of calcium compounds. It is produced either as powdered or precipitated calcium carbonate. The latter consists of finer particles of greater purity and more uniform size. They also have many important commercial apphcations. Various grades of precipitated calcium carbonate are used in several products, such as textiles, papers, paints, plastics, adhesives, sealants, and cosmetics. 

Industrial calcium carbonate (CaCOs) is mainly produced by extraction/milling of natural ore. Suitable ore-bodies include chalk, limestone, marble, and travertine. Sufficiently pure ore-bodies are selected to allow direct exploitation. The main applications include paper, paints, plastics, pharmaceuticals, etc. Luminescence and LIBS (Fig. 8.3) sorting may be used for calcium carbonate ore radiometric sorting. 

Calcium carbonate [471-34-1], CaC03, mol wt 100.09, occurs naturally as the principal constituent of limestone, marble, and chalk. Powdered calcium carbonate is produced by two methods on the industrial scale. It is quarried and ground from naturally occurring deposits and in some cases beneficiated. 

Calcium carbonate (CaCOj) is the starting point for most calcium compounds — and for oilier chemicals as well. It is found in nature in cliffs and mountain ranges in the form of chalk and limestone and marble. And it makes up the shells of clams and mussels and billions of tiny sea creatures. 

Although calcium is more metallic in character than magnesium, compounds of the two elements share some similar properties. Calcium carbonate, CaC03, occurs naturally as chalk and limestone. Marble is a dense form of calcium carbonate that can be given a high polish it is often colored by impurities, most commonly iron cations (Fig. 14.26). The two most common forms of pure calcium carbonate are calcite and aragonite. All these carbonates are the fossilized remains of marine life. Calcium carbonate decomposes to calcium oxide, CaO, or quicklime, when heated ... 

Many processes in nature require such a fine pH balance that they are dramatically upset by the shift that has occurred in the pH of rain. Thousands of lakes in the Adirondack region of upper New York State and in southeastern Canada have become so acidic that all fish life has disappeared. Massive tree die-offs have occurred throughout central and eastern Europe as acid rain has lowered the pH of the soil and leached nutrients from leaves. Countless marble statues have been slowly dissolved away as their calcium carbonate has been attacked by acid rain. 

Not all mine drainage or natural runoff from rock outcrops are acidic, even when extensive sulfide oxidation is present. Synthetic cyanide solutions, which are often used to extract gold and other metals from ores, can greatly increase the alkalinity of mining wastes and neutralize sulfuric acid (Craw et al., 1999). In other cases, the sulfuric acid is effectively neutralized by alkaline soils, limestones, dolostones, marbles, shams, or other carbonate-rich rocks (Pfeifer et al., 2004, 219 Razo et al., 2004 Lee, Lee and Lee, 2001, 491 Mendoza et al., 2006). Reactions between calcium carbonate and sulfuric acid may precipitate gypsum (CaS04 2H20). 

Some of the Group IA and IIA metals are found in nature in the form of carbonates, silicates, nitrates, and phosphates. For example, calcium carbonate is one of the most important naturally occurring compounds, and it is found in several forms. The most common form of calcium carbonate is limestone, which is used extensively as a building stone as well as the source of lime. Other forms include chalk, calcite, aragonite, Iceland spar, marble, and onyx. Many other materials such as egg shells, coral, pearls, and seashells are composed predominantly of calcium carbonate. Thus, it is one of the most widely occurring compounds in nature. 

Calcium does not occur as a free element in nature. It is much too active and always exists as a compound. The most common calcium compound is calcium carbonate (CaC03). It occurs in the minerals aragonite, calcite, chalk, limestone, marble, and travertine, and in oyster shells and coral. 

Calcium Calcium is an essential element for humans, especially in maintaining healthy bones and teeth. Calcium is found widely in nature, mainly combined with carbon and oxygen in calcium carbonate. This compound is the main ingredient in rocks such as limestone, chalk, and marble. Coral reefs build up from calcium carbonate exoskeletons that are created by marine animals called corals. Calcium carbonate is used in antacid tablets and as an abrasive in toothpaste. An abrasive is a hard material used to polish, smooth, or grind a softer material. Emery boards and sandpaper are examples of abrasive materials. 

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